Structured mesh for airfoil

doubtsincfd · November 20, 2009, 03:14

Hi!
I am trying to generate a structured mesh around an airfoil using Gridgen software. The grid should provide for implementation of periodic boundary condition (boundaries parallel to the flow direction). Also there is clustering near the leading edge of the airfoil. Is it possible to generate an O grid with these constraints? What type of grid will suffice these conditions? I tried using cartesian grid but because of the clustering requirement the aspect ratio of the cells near the top and bottom boundary becomes large (as the grid is clustered near the leading edge in x direction but the spacing increases in y direction as we move away from the airfoil)

jchawner · November 21, 2009, 09:51

Hello doubtsincfd.

In general, meshing an airfoil with H, O, C, or other topology is not a problem for Gridgen or any other decent software for that matter.

What I don't understand is the requirement for periodicity. Where exactly in the 2D O-grid will you be applying periodicity? There will be three boundaries: the outer farfield boundary, the airfoil surface, and the wake coming off the trailing edge and going to the outer boundary. The wake is an interblock connection or pass-thru boundary and won't be periodic. What am I misunderstanding?

doubtsincfd · November 21, 2009, 14:32

The airfoils are stacked one over other. In such case how can I apply periodic boundary condition on the far field boundary since the far field boundary will have an O or C shape?

jchawner · November 21, 2009, 16:16

Doubts:

It would be better if you could either attach a picture or email me your geometry in a format that Gridgen or Pointwise can read. Thanks.

doubtsincfd · November 22, 2009, 23:02

Or maybe I can simplify my problem....
What shape of domain(outer/far field boundary) should I use if I want to generate a structured grid for flow over stacked airfoils and if I want to simulate by using periodic boundary condition?
Thanks for the help!

jchawner · November 23, 2009, 08:31

Doubts:

Sounds like you might be doing a 2D simulation of a blade row in a turbomachine and need periodicity between the blades. Of course, the simplest topology would be to use a straight line for the periodic boundary. But that depends, of course, on the geometry of the blades and the other requirements of your grid like how fine it will be for accuracy near the blade surface and whether the surface topology will extend all the way to the outer boundary.

Don't hesitate to contact our Tech Support at 888-4PTWISE or support@pointwise.com - they'll be happy to help you work through all the options.

hoyos98 · March 7, 2022, 17:18

I suggest you visit https://aeroptimal.com/mesh (you must create an account to use this module), where you can create a full structured airfoil mesh - https://youtu.be/4Opu0zk7gFk . You can export .su2 .msh .foam .vtk

November 20, 2009, 03:14	Structured mesh for airfoil	#1
doubtsincfd Senior Member Join Date: Nov 2009 Location: Michigan Posts: 135 Rep Power: 16	Hi! I am trying to generate a structured mesh around an airfoil using Gridgen software. The grid should provide for implementation of periodic boundary condition (boundaries parallel to the flow direction). Also there is clustering near the leading edge of the airfoil. Is it possible to generate an O grid with these constraints? What type of grid will suffice these conditions? I tried using cartesian grid but because of the clustering requirement the aspect ratio of the cells near the top and bottom boundary becomes large (as the grid is clustered near the leading edge in x direction but the spacing increases in y direction as we move away from the airfoil)

November 21, 2009, 09:51		#2
jchawner Senior Member John Chawner Join Date: Mar 2009 Location: Fort Worth, Texas, USA Posts: 275 Rep Power: 18	Hello doubtsincfd. In general, meshing an airfoil with H, O, C, or other topology is not a problem for Gridgen or any other decent software for that matter. What I don't understand is the requirement for periodicity. Where exactly in the 2D O-grid will you be applying periodicity? There will be three boundaries: the outer farfield boundary, the airfoil surface, and the wake coming off the trailing edge and going to the outer boundary. The wake is an interblock connection or pass-thru boundary and won't be periodic. What am I misunderstanding? __________________ John Chawner / jrc@pointwise.com / www.pointwise.com Blog: http://blog.pointwise.com/ on Twitter: @jchawner

November 21, 2009, 16:16		#4
jchawner Senior Member John Chawner Join Date: Mar 2009 Location: Fort Worth, Texas, USA Posts: 275 Rep Power: 18	Doubts: It would be better if you could either attach a picture or email me your geometry in a format that Gridgen or Pointwise can read. Thanks. __________________ John Chawner / jrc@pointwise.com / www.pointwise.com Blog: http://blog.pointwise.com/ on Twitter: @jchawner

November 23, 2009, 08:31		#6
jchawner Senior Member John Chawner Join Date: Mar 2009 Location: Fort Worth, Texas, USA Posts: 275 Rep Power: 18	Doubts: Sounds like you might be doing a 2D simulation of a blade row in a turbomachine and need periodicity between the blades. Of course, the simplest topology would be to use a straight line for the periodic boundary. But that depends, of course, on the geometry of the blades and the other requirements of your grid like how fine it will be for accuracy near the blade surface and whether the surface topology will extend all the way to the outer boundary. Don't hesitate to contact our Tech Support at 888-4PTWISE or support@pointwise.com - they'll be happy to help you work through all the options. __________________ John Chawner / jrc@pointwise.com / www.pointwise.com Blog: http://blog.pointwise.com/ on Twitter: @jchawner

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November 21, 2009, 14:32		#3
doubtsincfd Senior Member Join Date: Nov 2009 Location: Michigan Posts: 135 Rep Power: 16	The airfoils are stacked one over other. In such case how can I apply periodic boundary condition on the far field boundary since the far field boundary will have an O or C shape?

November 22, 2009, 23:02		#5
doubtsincfd Senior Member Join Date: Nov 2009 Location: Michigan Posts: 135 Rep Power: 16	Or maybe I can simplify my problem.... What shape of domain(outer/far field boundary) should I use if I want to generate a structured grid for flow over stacked airfoils and if I want to simulate by using periodic boundary condition? Thanks for the help!

March 7, 2022, 17:18		#7
hoyos98 New Member jose daniel Join Date: Apr 2020 Posts: 26 Rep Power: 6	I suggest you visit https://aeroptimal.com/mesh (you must create an account to use this module), where you can create a full structured airfoil mesh - https://youtu.be/4Opu0zk7gFk . You can export .su2 .msh .foam .vtk